Wavefront aberrations of rotationally symmetric CGHs fabricated by a polar coordinate laser plotter

Abstract

Computer-generated holograms (CGHs) were fabricated by a polar coordinate laser plotter. The wavefront aberrations of these CGHs caused by fabrication inaccuracies were measured interferometrically. We tested Fresnel zone plates as typical examples of CGHs with focal ratios of ƒ/10 and ƒ/5 with a Fizeau interferometer. The tests comprised both binary phase holograms and binary amplitude holograms. The wavefront aberrations of the CGHs had an rms variation of about λ /50. Two types of aberrations were identified and could be referred to certain writing errors. Their size was deduced from the interferograms.